That sounds about right.My last car was a 2009 year car and was still on the original exhaust when i got rid of it last year.The garage where i traded it in said ,after the inspection, that it still had the date stamp visible.
I just did a quick search to confirm what I thought and 'afepower.com' has an article which states that most car exhausts nowadays are produced from Aluminised ('z' if American) steel. This has a surface coating of nearly pure Aluminium applied either by Vapour phase deposition or pack aluminising. This greatly enhaces resistance to corrosion at high temperatures, as demonstrated by its use on hot blades in gas turbines. Those of us old enough to remember uncoated Carbon Steel 3-year (or less) exhaust sysytems have reason to give thanks for the innovation.